This invention relates to a method and apparatus for cooling by conduction a large quantity of foodstuff and more specifically by circulating water cooled by its passage over an ice bank to an enclosure in conductive relationship with a container holding the foodstuff.
It has long been a problem in the food preparation industry to be able to comply with laws, both local and federal, which require that cooked food be cooled to a temperature of 40.degree. Fahrenheit or less within a time of 4 hours to thereby prevent the formation of harmful bacteria. This is not normally a problem with household food because the quantity is small and the domestic refrigerator can adequately cool it within the required time. Heretofore, when large quantities of food are involved, the only way of complying with these health laws was to divide the foodstuff into smaller quantities and cool them in a conventional refrigerator. This is obviously impractical for restaurants or large commercial institutions such as hospitals and the like which must prepare large quantities of foodstuff in advance of it being served. In addition, such cooling must take place without materially effecting the appearance of the food which would make it unsuitable for public consumption. For example, a foodstuff such as lasagna is usually prepared in large sheet-type pans a day in advance and must be rapidly cooled after cooking not only to comply with the aforementioned health laws but also to enable it to maintain its consistency and appearance the following day when it is reconstituted by heating and served.
Applicant has solved this problem by relying on the well-known method of heat transfer called conduction. Briefly, foodstuffs would be cooled by placing it usually in a container or directly on an enclosure such as a plate through which cooled water is circulated. The heat in the foodstuff passes directly through the bottom of the container into the enclosure and is absorbed by the cooled water. This cooling of the water circulated through the enclosure can be done by a conventional water chiller and again this may be satisfactory if the food is in small-size quantities. However, if the quantity of food is large or if it is very hot, the cooling capacity of the chiller would have to be impractically large and very complex to control the temperature of the water to prevent it from freezing. Such chillers would eventually cool the foodstuff, but it would take much longer than the legally mandated 4 hours.
Applicant has solved all of the heretofore mentioned problems of cooling large quantities of foodstuff within the mandated health temperature and time parameters for food sold or served to the general public by forming a thick bank of ice and circulating water over this ice bank and through the enclosure in conductive contact with the foodstuff itself or a container holding the foodstuff. This large reserve of 32.degree. water, which is stored in the form of ice as the latent heat is removed therefrom, permits the heat in large quantities of food to be rapidly withdrawn by conduction to the temperature of below 40.degree. Fahrenheit within the required 4 hours while using a relatively small amount of energy to create the bank of ice. This is because the ice can be built up on a plurality of plates in off hours when the cost of electricity is normally less and expended or melted in a relatively shorter time to achieve the aforementioned mandated degree of cooling and time frame.
It is therefore the primary object of the present invention to provide an apparatus and method for rapidly cooling large quantities of foodstuff.
It is another object of the present invention to provide an apparatus and method which is capable of cooling large quantities of foodstuff to the legally mandated requirement temperature of 40.degree. Fahrenheit within a time of 4 hours.
It is yet another object of the present invention to provide a novel ice bank construction for supplying a large quantity of cooled water for use in any distribution system requiring it.
It is still another object of the present invention to provide a method, apparatus and system for providing a large quantity of water over an extended period of time that is relatively inexpensive to build and operate when compared to water "chillers" presently being used.
These and other objects and advantages will become apparent to those skilled in the art when the foregoing is considered in conjunction with the following brief description of the drawings and detailed description of the preferred embodiments.